A bollard is a sturdy, short, vertical post. Although it originally described a post on a ship or quay used principally for mooring boats, the word is now used to describe posts installed to control road traffic and posts designed to prevent ram raiding and car ramming attacks.
The term is probably related to bole, meaning a tree trunk. The earliest citation given by the Oxford English Dictionary (referring to a maritime bollard) dates from 1844, although a reference in the Caledonian Mercury in 1817 describes bollards as huge posts. Previously, simpler terms such as "post" appear to have been used. The Norman-French name "Boulard" (still often found in Normandy) may be related.
From the 17th and 18th centuries, old cannon were often used as bollards on quaysides to help moor ships alongside. The cannon would be buried in the ground muzzle-first to approximately half or two-thirds of their length, leaving the breech (rear end) projecting above ground for attaching ropes. Such cannon can still occasionally be found. Ninteenth-century bollards were purpose-made, but often inherited a very similar "cannon" shape.
Wooden posts were used for basic traffic management from at least the beginning of the 18th century. An early well-documented case is that of the "two oak-posts" set up next to the medieval Eleanor cross at Waltham Cross, Hertfordshire, in 1721, at the expense of the Society of Antiquaries of London, "to secure Waltham Cross from injury by Carriages". Similar posts can be seen in many historic paintings and engravings.
In the Netherlands, the Amsterdammertjes of Amsterdam were first erected in the 19th century. They became popular symbols of the city, but they are now gradually being removed and replaced with elevated sidewalks.